From plastic pollution to global warming, the world’s oceans are facing immense challenges. Now a new study from the UK Centre for the Environment, Fisheries, and Aquaculture Science (CEFAS) states that rising acid levels in the marine ecosystem due to climate change can make industrial pollution even worse. The study shows that crustaceans have suffered significant DNA damage by eating contaminated particles of sediment containing metals which have been made more toxic by more acidic water.
CEFAS already monitors the sediments of human-altered estuaries (such as the Tees in Northeast England) for damaging metal particles. Sites such as this one must be regularly dredged in order to remain open for harbor traffic, and the excess material is tested for safety. Researchers placed crustaceans in tanks with the sediment along with seawater at the same acidity level found in the oceans today. They also ran a second test using the sediment and water at pH levels predicted 50 to 100 years from now. After ten days, the animals were evaluated and researchers found that DNA damage rose with acidification levels, suggesting that the pH was made more harmful in the presence of metals.
“The combined effect on these animals, of coping with adapting to climate change as well as increased toxin levels, could prove to be fatal,” remarked Dave Sheahan, senior researcher of the study.
The experiment also found that as toxin levels increase, animals can sometimes adjust their behavior to cope. Changes in burrowing behavior of certain species hinted at adaptation techniques. The scientists expect that some organisms will be able to fare better than others because of more robust genotypes and their ability to better tolerate changes, and possibly out-compete their neighbors. At present, commercially valuable species like lobsters and scallops are being looked at to see if they have been exposed to contaminants, and guidelines for sediment monitoring are being reassessed in light of the new information.